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Processing of Unsweetened Condensed Milk (Evaporated Milk)

By PMG Engineering ·

What is Unsweetened Condensed Milk?

Unsweetened condensed milk, also known as evaporated milk or dehydrated milk, is a concentrated milk product where approximately 60% of water is removed. Unlike sweetened condensed milk, it contains no added sugar, resulting in a slightly caramelized flavor due to high-heat sterilization (around 240°F).

It offers:

  • Longer shelf life
  • Higher nutrient and energy density
  • Added Vitamin D for improved nutritional value

Unsweetened condensed milk can be made from whole milk, skim milk, or recombined milk using skim milk powder, anhydrous milk fat (AMF), and water.

Manufacturing Process of Unsweetened Condensed Milk

1. Reception and Testing of Raw Milk

Milk is transported in refrigerated tankers from farms to the plant. Upon arrival, it is tested for:

  • Odor and taste
  • Bacterial content and sediment
  • Protein and fat composition

2. Standardization

The fat and solids-not-fat (SNF) content is adjusted to required levels. Typical compositions are:

  • Fat: 7.5%–9.0%
  • Non-fat milk solids: 18%–22%

3. Preheating / Pasteurization

Milk is preheated to:

  • Improve heat stability
  • Ensure optimum viscosity

4. Evaporation

Water is removed under vacuum (160–320 hPa) at 55°C–70°C using:

  • Multiple-effect evaporators
  • Falling film evaporators
  • Rising film or circulation evaporators
  • Horizontal tube evaporators

(A) Multiple-Effect Evaporator

Utilizes vapor from one vessel to heat the next, maximizing energy efficiency—a key solution in food engineering consulting.

 

(B) Falling Film Evaporator

Milk flows as a thin film inside vertically oriented tubes, where it boils and partially evaporates. It's efficient and preserves product quality.

5. Homogenization

High-pressure treatment breaks down fat globules to create a stable emulsion, preventing cream separation in the final product. 

 

6. Cooling

The homogenized milk is cooled to around 14°C, preparing it for further processing.

7. Canning

Automatic canning machines fill and seal the product before sterilization.

8. Sterilization

(a) Batch Autoclave:

Cans are placed in crates and sterilized together.

(b) Continuous Autoclave:

Cans pass on a conveyor belt through a controlled sterilization chamber.

Alternative Process Using UHT Technology

For UHT (Ultra High Temperature) Processing, steps 7 and 8 are replaced by:

10. UHT Treatment

Milk is heated to 122°C–140°C for 4 seconds to 2 minutes using a plate heat exchanger, ensuring sterility without damaging nutritional value.

11. Aseptic Filling

Milk is filled into pre-sterilized containers under aseptic conditions, extending shelf life while maintaining safety.

Flow Chart of Unsweetened Condensed Milk Processing

Conclusion

When evaluating a condensed milk product, remember:

  • Evaporated milk = Unsweetened condensed milk (no sugar)
  • Condensed milk = Sweetened product (contains added sugar)

PMG Engineering, your trusted food industry consultant, offers complete support for setting up dairy processing units, including evaporated milk production systems, aligned with international food safety standards and cost-effective automation solutions.

Frequently asked
What's the actual difference between evaporated milk and condensed milk on a spec sheet?
Evaporated milk is unsweetened condensed milk, also called dehydrated milk, with no added sugar. Condensed milk refers to the sweetened product containing added sugar. In both cases roughly 60% of the water is removed. Because unsweetened condensed milk relies on high-heat sterilization at around 240°F rather than sugar for preservation, it develops a slightly caramelized flavour and carries a longer shelf life.
What fat and SNF levels do we standardise to for evaporated milk?
For unsweetened condensed milk, standardisation adjusts fat and solids-not-fat before processing. Typical target compositions are fat of 7.5%–9.0% and non-fat milk solids of 18%–22%. Standardisation follows reception and testing of the raw milk, and precedes preheating or pasteurisation, which is carried out to improve heat stability and to ensure optimum viscosity in the concentrate.
Which evaporator type should we select for an evaporated milk line?
Water removal for unsweetened condensed milk is done under vacuum at 160–320 hPa and 55°C–70°C. Options include multiple-effect evaporators, falling film evaporators, rising film or circulation evaporators, and horizontal tube evaporators. Multiple-effect designs use vapour from one vessel to heat the next, maximising energy efficiency. Falling film units run milk as a thin film inside vertical tubes, which is efficient and preserves product quality.
Why is homogenisation necessary if the product is going to be sterilised anyway?
In unsweetened condensed milk production, homogenisation applies high-pressure treatment to break down fat globules and create a stable emulsion. This prevents cream separation in the finished canned or aseptic product. It is carried out after evaporation, and the homogenised milk is then cooled to around 14°C before canning or further processing.
Can we make evaporated milk without fresh milk supply?
Yes. Unsweetened condensed milk can be produced from whole milk, skim milk, or from recombined milk made using skim milk powder, anhydrous milk fat (AMF) and water. Whichever base is used, incoming raw milk arriving in refrigerated tankers is tested for odour and taste, bacterial content and sediment, and protein and fat composition before standardisation.
What changes in the process if we choose UHT instead of in-can sterilisation?
With conventional processing, unsweetened condensed milk is filled and sealed by automatic canning machines, then sterilised in a batch autoclave, where cans are sterilised together in crates, or a continuous autoclave with cans conveyed through a controlled chamber. With UHT, those two steps are replaced by heating to 122°C–140°C for 4 seconds to 2 minutes in a plate heat exchanger, followed by aseptic filling into pre-sterilised containers.
CITE THIS

PMG Engineering. (2021). Processing of Unsweetened Condensed Milk (Evaporated Milk). PMG Engineering. https://pmg.engineering/Article/96/processing-of-unsweetened-condensed-milk-evaporated-milk/

https://pmg.engineering/Article/96/processing-of-unsweetened-condensed-milk-evaporated-milk/